In many small factories the manufacturing takes place at different workstations containing one or several fixed machines. Manipulators, such as a robot, tending the machines or performing work tasks can be used in order to increase productivity, cost efficiency, quality or remove monotonous and hazardous work tasks. It is usually not economically feasible to install a robotic device at each working machine if the working machine has low utilization or the batch sizes are small. For small batch sizes, manual operation of the machines is wanted. Therefore, there is a need to easily move a robot unit between different workstations to obtain an optimal use of the robot and get easy manual access to the machines.
To improve the degree of use of the robot, the robot is placed on a movable platform, which is able to move between the workstations and connect to at least one docking station positioned at each workstation. The movable platform can be moved manually by hand or with a so called Automatic Guided Vehicle (AGV). The AGV may also be part of the platform. Through the connection to the docking station, the movable platform is fixed in a defined position in relation to the workstation. It is important for the robot to have a defined position in relation to the workstation to be able to perform complex and/or precise operations, such as welding, gluing, painting, grinding, picking, assembly, etc., at the workstation.
U.S. 2009/00906182 discloses a robot, which moves along a plurality of predefined paths between a plurality of workstations. Along the path the robot stops at each workstation and performs work at each work-station.
WO2010/043640 discloses an industrial robot system for working on a plurality of workstations. Each workstation is provided with a docking station comprising of protruding members extending into the work space. The robot is moved between the workstations by a movable platform. A connection device and a locking device are provided to connect and lock the platform to the docking station. A problem with the docking station disclosed in WO2010/043640 is that it is protruding and accordingly becomes an obstacle in the robot work area.